Pymongo skill

记录PyMongo的常用技巧

一次性更新多个字段

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way_bill = self.db.Waybill.update_one({"_id": waybill_id}, {
    '$set':{
        "user": self.user["_id"],
        "status": 1
    }    
})

mongodb小坑

pymong每次查询之后 只能进行一次迭代 建议将数据转化成list 

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all_waybills = list(self.db.Waybill.find({"status": 0}))
有多个or条件时，不同的字段的or条件要分开写，否则查询没有效果。 
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orders = list(self.db.Order.find({
    "$and":[
        {"content": {'$elemMatch': {'suppliers': self.user['_id']}}},
        {"$or": [
            {"status": 1},
            {"status": 2},
        ]},
        {"$or": [
            {"type": 2},
            {"type": 3},
            {"type": 4},
        ]}
    ]
}))

多条件筛选进行更新

尽量不使用update_many，使用update，也可达到一次更新多个的效果。

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_filter = {"order": _id, "status": 0}                      
self.db.Waybill.update(_filter, {"$set": {"status": status}})

或者 优先考虑使用这种方式 

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_filter = [{"order": _id}, {"status": 4}]
self.db.Waybill.update_many({"$and": _filter}, {"$set": {"status": 5}})

模糊匹配

目标对象

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{
    "_id": ObjectId("598bcb0fc3344d4511952921"),
    "arrivaltime": 1502592911,
    "contact": "鲁肃",a
    "contact_phone": "13589896969",
    "content": [
        {
            "type": 2,
            "name": "右江SPC16.6",
            "status": 0,
            "count": 0,
            "intorduce": "右江SPC16.6 最好的SPC16.6水泥",
            "price": 230,
            "suppliers": ObjectId("5979aaea132855361289842b"),
            "_id": ObjectId("598bcc03c3344d4511952922"),
            "account": "旺鑫户头",
            "origin_address": ObjectId("597bfb58c3344d6d584f595b"),
            "is_open": 1,
            "images": "http://opkf7ecvv.bkt.clouddn.com/FnK5A9P5h3F9CwlBV8gDWbk9at_x"
        }
    ],
    "count": 2,
    "createtime": 1502333711,
    "destination": "广西壮族自治区-百色市-西林县",
    "destination_detail": "八大河乡",
    "destination_location": "24.657053,104.498372",
    "freight": ObjectId("597dd0bbc3344d56153e6065"),
    "is_pay": 0,
    "load": 50,
    "origin": "广西壮族自治区-百色市-田阳县",
    "origin_detail": "华润水泥田阳有限公司",
    "origin_location": "23.757743,106.769572",
    "price": 23000,
    "status": 7,
    "type": 2,
    "user": ObjectId("5979b4a9132855361289842d")
}

匹配语法

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query = {"$and": [{'content': {'$elemMatch': {'suppliers': self.user['_id']}}}]}
orders = list(self.db.Order.find(query))

Python数据处理

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浮点数保留两位小数：float("%.2f" % unpdate_content["price"])
Python后端开发

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